Physical vapor deposition is a coating process extensively used to apply ceramic thermal barrier coatings on turbine airfoils by electron beam evaporation. Extensive work has been done to design coating processes and associated fixturing to apply a uniform coating on a variety of airfoil sizes and shapes. Workpieces to be coated need to be manipulated in the vapor to achieve uniform coverage with sections of the workpiece that do not require a coating need to be masked adequately. Prior to and/or after the actual coating application, however, the same workpieces often are subjected to preparation and finishing processes.
U.S. Pat. No. 5,997,947 discloses a modular, rotisserie type coating fixture for use in electronic beam physical vapor deposition (EBPVD) coating processes. Tooling fixtures used in the EBPVD coating process generally include a support structure and means to couple the support structure and allow it to be rotated about a first axis. The tooling fixture further includes a cassette means within the support structure for holding one or more workpieces to be coated in place. The cassette means are joined to the support structure by spindles which allow the cassette means to rotate about a second axis substantially parallel to the first axis and thereby allow each workpiece being coated to rotate about its longitudinal axis. The cassette means support each workpiece so that surfaces of the airfoil to be coated are maintained substantially parallel to the coating source. This fixture is useful only for the coating process and generally not useful for any preparation or finishing steps that the workpieces may be subjected to.
U.S. Pat. No. 7,837,843 discloses another rotisserie type tooling fixture assembly for use in a physical vapor deposition coating operation which comprises a cylindrical type support structure comprising a circular base member, a circular top member opposite the circular base member, and a plurality of structural members joining the top member to said base member. The workpieces are arranged in a plurality of panel members aligned in a staggered vertical direction around the outer periphery of said support structure forming the cylinder-like structure. Again, this tooling fixture assembly is specifically designed for the EBPVD coating process and not particularly useful for any preparation or finishing processes that the workpieces may be subjected to.
What is needed therefore is a tooling fixture assembly or portions thereof that can be used in several different preparation, coating and finishing steps without the need to disassemble and re-assemble the workpieces into the tooling fixture assembly.